During the manufacture of integrated circuits, the processing of the semiconductor layers that form the circuitry of the integrated circuit is one of the most critical steps. In fact, as integrated circuit processor designs increase in complexity, the need to maximize the yield at every layering step becomes increasingly important.
Heretofore in this field, electronic systems such as computers, cellular telephones, etc., were built with individual components that were assembled on a circuit board. For example, an electronic system such as a computer generally includes a microprocessor, an input/output or bus interface, a memory cache, keyboard control circuits, video circuits, and a floppy disk drive, hard disk drive and/or CD-ROM control circuits. The central component of the electronic system is the processor, now generally called a microprocessor to indicate the decreasing size of the individual electronic components.
Using the microprocessor that forms part of the electronic system, as an example, it can be observed that the following evolution has occurred. The creation of the logic that forms the main component of the microprocessor on a single silicon substrate was a first step. A second step was to decrease the distance between the logic of the processor and the bit buffering components that the microprocessor uses to control processor flow by creating a single chip containing the microprocessor and a cache memory. A third step was the integration of a microprocessor, cache memory and an input/output bus interface, also on a single chip.
United States Letters Patent No. 5,561,594, issued Oct. 1, 1996 (SGS-Thomson Microelectronics, Ltd.) discloses an electrical assembly in which the electrical component is mounted on a multi-layer printed circuit board having a plurality of conducting pins located in perforations within the board. The conducting pins located in the board have pointed ends that project above the board and make electric contact with solder bumps on the electrical component. The specification describes an apparatus and method for flip-chip packaging. As with conventional manufacturing, the printed circuit board has standard size vias that are drilled through for each individual substrate.
United States Letters Patent No. 5,621,193, issued Apr. 15, 1997 (Northrop Grumman Corp.) discloses a method for electrically connecting surface conductors to edge conductors by use of an intersecting side non-conductor substrate having a through hole in the substrate and metalization of the through hole. The electrical connections between the surface and the side include forming an intersecting ceiling plug in the via prior to cutting the intersecting side.